If you can reasonably throw up a new wall and closet, turning a 3 bed into a 4 bed, that is a great place to start, but only if it works for the property and you have at least 2 full bathrooms.  

Originally posted by @Michele Davidson:@Alex YeaterWe are selling our bed and breakfast business complete and turn key with wedding items.

I generally rule out most single family homes as viable rentals, as prices are pretty high relative to rents, so aside from some downtown neighborhoods, typically you do not find large areas of single family rental neighborhoods (a median sale price on a 3 bed, 2 bath home so far this year in Dane County on MLS sales data is at $430k). 

If you're going to work with contractors, collect rent from tenants, or try to bed the hot chick at the bar, you better learn to recognize warning signs and get out early. 

Other than that, it plays no role and has no relevance to the mortgage acceleration scenario.I'm going to bed. 

This is a 2500 sq foot 3 bed 2 bath both sides.

Small college town, 10k-30k people, anywhere from 80k-160k will get you a nice 3 bed 1 bath house.

Its 2700 sq ft, 5 bed 2 bath (basement is unfinished and you can finish the 3rd bath).

They are either landlocked or the road leading to it and often than land itself sits inside a dry creek bed known as an arroyo that floods whenever it rains upstream.

These are all going to be 2 bed 1 bath a little less than 700 sq ft.